In the first of a new regular column, Adler & Allan’s Managing Director, Mike Williamson MBE, explains how we can reduce pollution, enhance the resilience of our water systems, and protect the environment for future generations, by tackling the four ‘I’s.
One of the most significant issues in managing water quality and reducing pollution is the volume of water entering the network. I believe this is influenced by four key factors: inflow, infiltration, ingress, and inundation. These elements, collectively known as the four ‘I’s, have a profound impact on pollution levels and the overall efficiency of our water systems.
Understanding the four ‘I’s
Inflow refers to the water that enters the sewer system from sources such as stormwater drains and surface runoff. This can occur during heavy rainfall when water flows directly into the sewer network.
Infiltration is the process by which groundwater seeps into the sewer system through cracks and leaks in pipes.
Ingress involves the entry of water from external sources, such as rivers or lakes, into the sewer system.
Inundation is the flooding of the sewer system due to extreme weather events or high tides. Each of these factors contributes to the overall volume of water in the network, which can lead to significant pollution challenges.
The impact on pollution
The presence of excess water in the sewer system can dilute wastewater, making it more difficult to treat effectively. This can result in untreated or partially treated sewage being discharged into the environment, leading to pollution of rivers, lakes, and coastal areas. Additionally, the increased volume of water can overwhelm treatment plants, causing them to operate less efficiently and increasing the risk of system failures.
Inflow can introduce pollutants from urban runoff, such as oils, heavy metals, and chemicals, into the sewer system. Infiltration can bring contaminants from groundwater, including nitrates and pesticides, into the network. Ingress can introduce pollutants from external water bodies, such as sediments and organic matter. Inundation can cause sewer overflows, leading to the release of untreated sewage into the environment. Each of these scenarios poses a significant risk to water quality and public health.
Strategies for reducing water entry
To mitigate the impact of the four ‘I’s on pollution, a multifaceted approach is required. This includes improving infrastructure, enhancing monitoring and detection systems, and implementing preventative measures. The aim is to improve the overall effectiveness of the wastewater network!
Infrastructure improvements
Upgrading and maintaining sewer systems to prevent leaks and cracks can significantly reduce infiltration. There are a variety of techniques available, depending on the ground and environment, and technological innovation will continue to make this an area where large gains can be made. Installing backflow prevention devices can help manage inflow and ingress. Enhancing flood defences can mitigate the risk of inundation.
Monitoring and detection
Implementing advanced monitoring systems to detect and quantify inflow, infiltration, ingress, and inundation can provide valuable data for managing water entry. This includes using sensors and remote monitoring technologies to identify problem areas and respond quickly to issues.
Preventative measures
Developing green infrastructure solutions, such as permeable pavements and rain gardens, can reduce surface runoff and inflow. Implementing land use planning and zoning regulations to protect vulnerable areas from inundation can also be effective. Encouraging the use of sustainable drainage systems (SuDS) can help manage water entry and reduce pollution.
Misconnections need to be addressed too. This must be done at scale and involves survey and rectification. Both survey and rectification should be conducted by trained wastewater specialists, who appreciate and understand that need to improve the overall effectiveness of the network.
Conclusion
Reducing the volume of water entering the sewer network is crucial for managing pollution and ensuring the efficiency of our networks. By addressing the four ‘I’s with innovative solutions and a collaborative approach, we can mitigate their impact on water quality and public health.
In conclusion, the challenge of managing water entry into the sewer network requires a comprehensive strategy that includes infrastructure improvements, advanced monitoring, and preventative measures. By tackling the four ‘I’s head-on, we can reduce pollution, enhance the resilience of our water systems, and protect the environment for future generations.
